JSI Tip 1418. Still more on "Your message was deleted without being read".

In tip 1405 and tip 1415, we described two reasons for the subject message. Here is another common one:

IF you have enabled Tell me when all messages have been read in Outlook,AND you send a message,AND the recipient uses the Exchange Client to transfer the message to the Offline Exchange Store on their laptop ,THEN you receive the subject message.